WEDNESDAY, Dec. 20, 2017 (HealthDay News) -- Children who inhale coarse particles -- like dust, sand or even rubber emissions from tires -- increase their chances of developing serious asthma, new research indicates.

The finding comes from the analysis of data on 8 million young people, 5 to 20 years old, in 34 U.S. states.

It focused on the impact of their exposure to tiny bits of so-called "coarse" matter that are far thinner than a human hair.

In the end, investigators from the Johns Hopkins School of Medicine determined that the more a child is exposed to such coarse matter, the more their asthma risk increased.

"Regulation and monitoring of this part of air pollution may need to be considered," study first author Dr. Corinne Keet said in a news release from Johns Hopkins Medicine. She is an associated professor of pediatrics at the medical school.

Specifically, Keet and colleagues tallied the amount of coarse particles in the air from various neighborhoods, measured in micrograms of particles per cubic meter of air. For each increase in microgram/cubic meter of particulate matter, asthma risk went up by 0.6 percent, the researchers found.

Each additional increase of exposure also upped the likelihood of an emergency room visit for an asthma-related concern by 1.7 percent and asthma-driven hospitalizations by 2.3 percent.

Children 11 years old or younger appeared to be particularly vulnerable to such exposure -- perhaps because they spend more time outdoors and their lungs are still developing at that age, the researchers said.

An estimated 7.1 million children currently have asthma, making it the most common chronic pediatric illness, the researchers noted.

Their findings were published online Dec. 15 in the American Journal of Respiratory and Critical Care Medicine.